1. Field of the Invention
The present invention relates to an object, a method, a manufacturing method, a process, a machine, a manufacture, or a composition of matter. The present invention relates to, for example, a semiconductor device, a display device, a light-emitting device, a driving method thereof, or a manufacturing method thereof. In particular, the present invention relates to a microprocessor and a method for driving the microprocessor.
Note that the term “microprocessor” in this specification can be regarded as a synonym for the term “CPU”, “MPU”, “processor”, or the like.
2. Description of the Related Art
With the development of a technique for miniaturizing a semiconductor device, the degree of integration of a microprocessor has been increased year by year. Accordingly, the total amount of leakage current of a variety of semiconductor elements (e.g., a transistor and the like) provided inside the microprocessor has been increased, which has resulted in a large increase in power consumption of the microprocessor. Thus, one of important issues in recent years is to reduce power consumption of a microprocessor.
As one of methods for reducing power consumption of a microprocessor, there is a technique in which a circuit block which does not need to operate in the microprocessor is switched to a low power consumption mode (Patent Document 1). In Patent Document 1, a stop of supply of power supply voltage to a block which does not need to operate is given as the low power consumption mode, for example.